CGExprAgg.cpp revision f871d0cc377a1367b519a6cce26be74607566eba
1//===--- CGExprAgg.cpp - Emit LLVM Code from Aggregate Expressions --------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This contains code to emit Aggregate Expr nodes as LLVM code. 11// 12//===----------------------------------------------------------------------===// 13 14#include "CodeGenFunction.h" 15#include "CodeGenModule.h" 16#include "CGObjCRuntime.h" 17#include "clang/AST/ASTContext.h" 18#include "clang/AST/DeclCXX.h" 19#include "clang/AST/StmtVisitor.h" 20#include "llvm/Constants.h" 21#include "llvm/Function.h" 22#include "llvm/GlobalVariable.h" 23#include "llvm/Intrinsics.h" 24using namespace clang; 25using namespace CodeGen; 26 27//===----------------------------------------------------------------------===// 28// Aggregate Expression Emitter 29//===----------------------------------------------------------------------===// 30 31namespace { 32class AggExprEmitter : public StmtVisitor<AggExprEmitter> { 33 CodeGenFunction &CGF; 34 CGBuilderTy &Builder; 35 llvm::Value *DestPtr; 36 bool VolatileDest; 37 bool IgnoreResult; 38 bool IsInitializer; 39 bool RequiresGCollection; 40 41 ReturnValueSlot getReturnValueSlot() const { 42 // If the destination slot requires garbage collection, we can't 43 // use the real return value slot, because we have to use the GC 44 // API. 45 if (RequiresGCollection) return ReturnValueSlot(); 46 47 return ReturnValueSlot(DestPtr, VolatileDest); 48 } 49 50public: 51 AggExprEmitter(CodeGenFunction &cgf, llvm::Value *destPtr, bool v, 52 bool ignore, bool isinit, bool requiresGCollection) 53 : CGF(cgf), Builder(CGF.Builder), 54 DestPtr(destPtr), VolatileDest(v), IgnoreResult(ignore), 55 IsInitializer(isinit), RequiresGCollection(requiresGCollection) { 56 } 57 58 //===--------------------------------------------------------------------===// 59 // Utilities 60 //===--------------------------------------------------------------------===// 61 62 /// EmitAggLoadOfLValue - Given an expression with aggregate type that 63 /// represents a value lvalue, this method emits the address of the lvalue, 64 /// then loads the result into DestPtr. 65 void EmitAggLoadOfLValue(const Expr *E); 66 67 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. 68 void EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore = false); 69 void EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore = false); 70 71 void EmitGCMove(const Expr *E, RValue Src); 72 73 bool TypeRequiresGCollection(QualType T); 74 75 //===--------------------------------------------------------------------===// 76 // Visitor Methods 77 //===--------------------------------------------------------------------===// 78 79 void VisitStmt(Stmt *S) { 80 CGF.ErrorUnsupported(S, "aggregate expression"); 81 } 82 void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); } 83 void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); } 84 85 // l-values. 86 void VisitDeclRefExpr(DeclRefExpr *DRE) { EmitAggLoadOfLValue(DRE); } 87 void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); } 88 void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); } 89 void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); } 90 void VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { 91 EmitAggLoadOfLValue(E); 92 } 93 void VisitArraySubscriptExpr(ArraySubscriptExpr *E) { 94 EmitAggLoadOfLValue(E); 95 } 96 void VisitBlockDeclRefExpr(const BlockDeclRefExpr *E) { 97 EmitAggLoadOfLValue(E); 98 } 99 void VisitPredefinedExpr(const PredefinedExpr *E) { 100 EmitAggLoadOfLValue(E); 101 } 102 103 // Operators. 104 void VisitCastExpr(CastExpr *E); 105 void VisitCallExpr(const CallExpr *E); 106 void VisitStmtExpr(const StmtExpr *E); 107 void VisitBinaryOperator(const BinaryOperator *BO); 108 void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO); 109 void VisitBinAssign(const BinaryOperator *E); 110 void VisitBinComma(const BinaryOperator *E); 111 void VisitUnaryAddrOf(const UnaryOperator *E); 112 113 void VisitObjCMessageExpr(ObjCMessageExpr *E); 114 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) { 115 EmitAggLoadOfLValue(E); 116 } 117 void VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E); 118 void VisitObjCImplicitSetterGetterRefExpr(ObjCImplicitSetterGetterRefExpr *E); 119 120 void VisitConditionalOperator(const ConditionalOperator *CO); 121 void VisitChooseExpr(const ChooseExpr *CE); 122 void VisitInitListExpr(InitListExpr *E); 123 void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E); 124 void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) { 125 Visit(DAE->getExpr()); 126 } 127 void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E); 128 void VisitCXXConstructExpr(const CXXConstructExpr *E); 129 void VisitCXXExprWithTemporaries(CXXExprWithTemporaries *E); 130 void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E); 131 void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); } 132 133 void VisitVAArgExpr(VAArgExpr *E); 134 135 void EmitInitializationToLValue(Expr *E, LValue Address, QualType T); 136 void EmitNullInitializationToLValue(LValue Address, QualType T); 137 // case Expr::ChooseExprClass: 138 void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); } 139}; 140} // end anonymous namespace. 141 142//===----------------------------------------------------------------------===// 143// Utilities 144//===----------------------------------------------------------------------===// 145 146/// EmitAggLoadOfLValue - Given an expression with aggregate type that 147/// represents a value lvalue, this method emits the address of the lvalue, 148/// then loads the result into DestPtr. 149void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) { 150 LValue LV = CGF.EmitLValue(E); 151 EmitFinalDestCopy(E, LV); 152} 153 154/// \brief True if the given aggregate type requires special GC API calls. 155bool AggExprEmitter::TypeRequiresGCollection(QualType T) { 156 // Only record types have members that might require garbage collection. 157 const RecordType *RecordTy = T->getAs<RecordType>(); 158 if (!RecordTy) return false; 159 160 // Don't mess with non-trivial C++ types. 161 RecordDecl *Record = RecordTy->getDecl(); 162 if (isa<CXXRecordDecl>(Record) && 163 (!cast<CXXRecordDecl>(Record)->hasTrivialCopyConstructor() || 164 !cast<CXXRecordDecl>(Record)->hasTrivialDestructor())) 165 return false; 166 167 // Check whether the type has an object member. 168 return Record->hasObjectMember(); 169} 170 171/// \brief Perform the final move to DestPtr if RequiresGCollection is set. 172/// 173/// The idea is that you do something like this: 174/// RValue Result = EmitSomething(..., getReturnValueSlot()); 175/// EmitGCMove(E, Result); 176/// If GC doesn't interfere, this will cause the result to be emitted 177/// directly into the return value slot. If GC does interfere, a final 178/// move will be performed. 179void AggExprEmitter::EmitGCMove(const Expr *E, RValue Src) { 180 if (RequiresGCollection) { 181 std::pair<uint64_t, unsigned> TypeInfo = 182 CGF.getContext().getTypeInfo(E->getType()); 183 unsigned long size = TypeInfo.first/8; 184 const llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType()); 185 llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size); 186 CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF, DestPtr, 187 Src.getAggregateAddr(), 188 SizeVal); 189 } 190} 191 192/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. 193void AggExprEmitter::EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore) { 194 assert(Src.isAggregate() && "value must be aggregate value!"); 195 196 // If the result is ignored, don't copy from the value. 197 if (DestPtr == 0) { 198 if (!Src.isVolatileQualified() || (IgnoreResult && Ignore)) 199 return; 200 // If the source is volatile, we must read from it; to do that, we need 201 // some place to put it. 202 DestPtr = CGF.CreateMemTemp(E->getType(), "agg.tmp"); 203 } 204 205 if (RequiresGCollection) { 206 std::pair<uint64_t, unsigned> TypeInfo = 207 CGF.getContext().getTypeInfo(E->getType()); 208 unsigned long size = TypeInfo.first/8; 209 const llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType()); 210 llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size); 211 CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF, 212 DestPtr, Src.getAggregateAddr(), 213 SizeVal); 214 return; 215 } 216 // If the result of the assignment is used, copy the LHS there also. 217 // FIXME: Pass VolatileDest as well. I think we also need to merge volatile 218 // from the source as well, as we can't eliminate it if either operand 219 // is volatile, unless copy has volatile for both source and destination.. 220 CGF.EmitAggregateCopy(DestPtr, Src.getAggregateAddr(), E->getType(), 221 VolatileDest|Src.isVolatileQualified()); 222} 223 224/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. 225void AggExprEmitter::EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore) { 226 assert(Src.isSimple() && "Can't have aggregate bitfield, vector, etc"); 227 228 EmitFinalDestCopy(E, RValue::getAggregate(Src.getAddress(), 229 Src.isVolatileQualified()), 230 Ignore); 231} 232 233//===----------------------------------------------------------------------===// 234// Visitor Methods 235//===----------------------------------------------------------------------===// 236 237void AggExprEmitter::VisitCastExpr(CastExpr *E) { 238 if (!DestPtr && E->getCastKind() != CastExpr::CK_Dynamic) { 239 Visit(E->getSubExpr()); 240 return; 241 } 242 243 switch (E->getCastKind()) { 244 default: assert(0 && "Unhandled cast kind!"); 245 246 case CastExpr::CK_Dynamic: { 247 assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?"); 248 LValue LV = CGF.EmitCheckedLValue(E->getSubExpr()); 249 // FIXME: Do we also need to handle property references here? 250 if (LV.isSimple()) 251 CGF.EmitDynamicCast(LV.getAddress(), cast<CXXDynamicCastExpr>(E)); 252 else 253 CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast"); 254 255 if (DestPtr) 256 CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination"); 257 break; 258 } 259 260 case CastExpr::CK_ToUnion: { 261 // GCC union extension 262 QualType PtrTy = 263 CGF.getContext().getPointerType(E->getSubExpr()->getType()); 264 llvm::Value *CastPtr = Builder.CreateBitCast(DestPtr, 265 CGF.ConvertType(PtrTy)); 266 EmitInitializationToLValue(E->getSubExpr(), 267 LValue::MakeAddr(CastPtr, Qualifiers()), 268 E->getSubExpr()->getType()); 269 break; 270 } 271 272 case CastExpr::CK_DerivedToBase: 273 case CastExpr::CK_BaseToDerived: 274 case CastExpr::CK_UncheckedDerivedToBase: { 275 assert(0 && "cannot perform hierarchy conversion in EmitAggExpr: " 276 "should have been unpacked before we got here"); 277 break; 278 } 279 280 // FIXME: Remove the CK_Unknown check here. 281 case CastExpr::CK_Unknown: 282 case CastExpr::CK_NoOp: 283 case CastExpr::CK_UserDefinedConversion: 284 case CastExpr::CK_ConstructorConversion: 285 assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(), 286 E->getType()) && 287 "Implicit cast types must be compatible"); 288 Visit(E->getSubExpr()); 289 break; 290 291 case CastExpr::CK_NullToMemberPointer: { 292 // If the subexpression's type is the C++0x nullptr_t, emit the 293 // subexpression, which may have side effects. 294 if (E->getSubExpr()->getType()->isNullPtrType()) 295 Visit(E->getSubExpr()); 296 297 const llvm::Type *PtrDiffTy = 298 CGF.ConvertType(CGF.getContext().getPointerDiffType()); 299 300 llvm::Value *NullValue = llvm::Constant::getNullValue(PtrDiffTy); 301 llvm::Value *Ptr = Builder.CreateStructGEP(DestPtr, 0, "ptr"); 302 Builder.CreateStore(NullValue, Ptr, VolatileDest); 303 304 llvm::Value *Adj = Builder.CreateStructGEP(DestPtr, 1, "adj"); 305 Builder.CreateStore(NullValue, Adj, VolatileDest); 306 307 break; 308 } 309 310 case CastExpr::CK_LValueBitCast: 311 llvm_unreachable("there are no lvalue bit-casts on aggregates"); 312 break; 313 314 case CastExpr::CK_BitCast: { 315 // This must be a member function pointer cast. 316 Visit(E->getSubExpr()); 317 break; 318 } 319 320 case CastExpr::CK_DerivedToBaseMemberPointer: 321 case CastExpr::CK_BaseToDerivedMemberPointer: { 322 QualType SrcType = E->getSubExpr()->getType(); 323 324 llvm::Value *Src = CGF.CreateMemTemp(SrcType, "tmp"); 325 CGF.EmitAggExpr(E->getSubExpr(), Src, SrcType.isVolatileQualified()); 326 327 llvm::Value *SrcPtr = Builder.CreateStructGEP(Src, 0, "src.ptr"); 328 SrcPtr = Builder.CreateLoad(SrcPtr); 329 330 llvm::Value *SrcAdj = Builder.CreateStructGEP(Src, 1, "src.adj"); 331 SrcAdj = Builder.CreateLoad(SrcAdj); 332 333 llvm::Value *DstPtr = Builder.CreateStructGEP(DestPtr, 0, "dst.ptr"); 334 Builder.CreateStore(SrcPtr, DstPtr, VolatileDest); 335 336 llvm::Value *DstAdj = Builder.CreateStructGEP(DestPtr, 1, "dst.adj"); 337 338 // Now See if we need to update the adjustment. 339 const CXXRecordDecl *BaseDecl = 340 cast<CXXRecordDecl>(SrcType->getAs<MemberPointerType>()-> 341 getClass()->getAs<RecordType>()->getDecl()); 342 const CXXRecordDecl *DerivedDecl = 343 cast<CXXRecordDecl>(E->getType()->getAs<MemberPointerType>()-> 344 getClass()->getAs<RecordType>()->getDecl()); 345 if (E->getCastKind() == CastExpr::CK_DerivedToBaseMemberPointer) 346 std::swap(DerivedDecl, BaseDecl); 347 348 if (llvm::Constant *Adj = 349 CGF.CGM.GetNonVirtualBaseClassOffset(DerivedDecl, 350 E->path_begin(), 351 E->path_end())) { 352 if (E->getCastKind() == CastExpr::CK_DerivedToBaseMemberPointer) 353 SrcAdj = Builder.CreateSub(SrcAdj, Adj, "adj"); 354 else 355 SrcAdj = Builder.CreateAdd(SrcAdj, Adj, "adj"); 356 } 357 358 Builder.CreateStore(SrcAdj, DstAdj, VolatileDest); 359 break; 360 } 361 } 362} 363 364void AggExprEmitter::VisitCallExpr(const CallExpr *E) { 365 if (E->getCallReturnType()->isReferenceType()) { 366 EmitAggLoadOfLValue(E); 367 return; 368 } 369 370 RValue RV = CGF.EmitCallExpr(E, getReturnValueSlot()); 371 EmitGCMove(E, RV); 372} 373 374void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) { 375 RValue RV = CGF.EmitObjCMessageExpr(E, getReturnValueSlot()); 376 EmitGCMove(E, RV); 377} 378 379void AggExprEmitter::VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E) { 380 RValue RV = CGF.EmitObjCPropertyGet(E, getReturnValueSlot()); 381 EmitGCMove(E, RV); 382} 383 384void AggExprEmitter::VisitObjCImplicitSetterGetterRefExpr( 385 ObjCImplicitSetterGetterRefExpr *E) { 386 RValue RV = CGF.EmitObjCPropertyGet(E, getReturnValueSlot()); 387 EmitGCMove(E, RV); 388} 389 390void AggExprEmitter::VisitBinComma(const BinaryOperator *E) { 391 CGF.EmitAnyExpr(E->getLHS(), 0, false, true); 392 CGF.EmitAggExpr(E->getRHS(), DestPtr, VolatileDest, 393 /*IgnoreResult=*/false, IsInitializer); 394} 395 396void AggExprEmitter::VisitUnaryAddrOf(const UnaryOperator *E) { 397 // We have a member function pointer. 398 const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>(); 399 (void) MPT; 400 assert(MPT->getPointeeType()->isFunctionProtoType() && 401 "Unexpected member pointer type!"); 402 403 // The creation of member function pointers has no side effects; if 404 // there is no destination pointer, we have nothing to do. 405 if (!DestPtr) 406 return; 407 408 const DeclRefExpr *DRE = cast<DeclRefExpr>(E->getSubExpr()); 409 const CXXMethodDecl *MD = 410 cast<CXXMethodDecl>(DRE->getDecl())->getCanonicalDecl(); 411 412 const llvm::Type *PtrDiffTy = 413 CGF.ConvertType(CGF.getContext().getPointerDiffType()); 414 415 llvm::Value *DstPtr = Builder.CreateStructGEP(DestPtr, 0, "dst.ptr"); 416 llvm::Value *FuncPtr = CGF.CGM.GetCXXMemberFunctionPointerValue(MD); 417 Builder.CreateStore(FuncPtr, DstPtr, VolatileDest); 418 419 llvm::Value *AdjPtr = Builder.CreateStructGEP(DestPtr, 1, "dst.adj"); 420 // The adjustment will always be 0. 421 Builder.CreateStore(llvm::ConstantInt::get(PtrDiffTy, 0), AdjPtr, 422 VolatileDest); 423} 424 425void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) { 426 CGF.EmitCompoundStmt(*E->getSubStmt(), true, DestPtr, VolatileDest); 427} 428 429void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) { 430 if (E->getOpcode() == BinaryOperator::PtrMemD || 431 E->getOpcode() == BinaryOperator::PtrMemI) 432 VisitPointerToDataMemberBinaryOperator(E); 433 else 434 CGF.ErrorUnsupported(E, "aggregate binary expression"); 435} 436 437void AggExprEmitter::VisitPointerToDataMemberBinaryOperator( 438 const BinaryOperator *E) { 439 LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E); 440 EmitFinalDestCopy(E, LV); 441} 442 443void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) { 444 // For an assignment to work, the value on the right has 445 // to be compatible with the value on the left. 446 assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(), 447 E->getRHS()->getType()) 448 && "Invalid assignment"); 449 LValue LHS = CGF.EmitLValue(E->getLHS()); 450 451 // We have to special case property setters, otherwise we must have 452 // a simple lvalue (no aggregates inside vectors, bitfields). 453 if (LHS.isPropertyRef()) { 454 llvm::Value *AggLoc = DestPtr; 455 if (!AggLoc) 456 AggLoc = CGF.CreateMemTemp(E->getRHS()->getType()); 457 CGF.EmitAggExpr(E->getRHS(), AggLoc, VolatileDest); 458 CGF.EmitObjCPropertySet(LHS.getPropertyRefExpr(), 459 RValue::getAggregate(AggLoc, VolatileDest)); 460 } else if (LHS.isKVCRef()) { 461 llvm::Value *AggLoc = DestPtr; 462 if (!AggLoc) 463 AggLoc = CGF.CreateMemTemp(E->getRHS()->getType()); 464 CGF.EmitAggExpr(E->getRHS(), AggLoc, VolatileDest); 465 CGF.EmitObjCPropertySet(LHS.getKVCRefExpr(), 466 RValue::getAggregate(AggLoc, VolatileDest)); 467 } else { 468 bool RequiresGCollection = false; 469 if (CGF.getContext().getLangOptions().getGCMode()) 470 RequiresGCollection = TypeRequiresGCollection(E->getLHS()->getType()); 471 472 // Codegen the RHS so that it stores directly into the LHS. 473 CGF.EmitAggExpr(E->getRHS(), LHS.getAddress(), LHS.isVolatileQualified(), 474 false, false, RequiresGCollection); 475 EmitFinalDestCopy(E, LHS, true); 476 } 477} 478 479void AggExprEmitter::VisitConditionalOperator(const ConditionalOperator *E) { 480 if (!E->getLHS()) { 481 CGF.ErrorUnsupported(E, "conditional operator with missing LHS"); 482 return; 483 } 484 485 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true"); 486 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false"); 487 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end"); 488 489 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock); 490 491 CGF.BeginConditionalBranch(); 492 CGF.EmitBlock(LHSBlock); 493 494 // Handle the GNU extension for missing LHS. 495 assert(E->getLHS() && "Must have LHS for aggregate value"); 496 497 Visit(E->getLHS()); 498 CGF.EndConditionalBranch(); 499 CGF.EmitBranch(ContBlock); 500 501 CGF.BeginConditionalBranch(); 502 CGF.EmitBlock(RHSBlock); 503 504 Visit(E->getRHS()); 505 CGF.EndConditionalBranch(); 506 CGF.EmitBranch(ContBlock); 507 508 CGF.EmitBlock(ContBlock); 509} 510 511void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) { 512 Visit(CE->getChosenSubExpr(CGF.getContext())); 513} 514 515void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) { 516 llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr()); 517 llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType()); 518 519 if (!ArgPtr) { 520 CGF.ErrorUnsupported(VE, "aggregate va_arg expression"); 521 return; 522 } 523 524 EmitFinalDestCopy(VE, LValue::MakeAddr(ArgPtr, Qualifiers())); 525} 526 527void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) { 528 llvm::Value *Val = DestPtr; 529 530 if (!Val) { 531 // Create a temporary variable. 532 Val = CGF.CreateMemTemp(E->getType(), "tmp"); 533 534 // FIXME: volatile 535 CGF.EmitAggExpr(E->getSubExpr(), Val, false); 536 } else 537 Visit(E->getSubExpr()); 538 539 // Don't make this a live temporary if we're emitting an initializer expr. 540 if (!IsInitializer) 541 CGF.EmitCXXTemporary(E->getTemporary(), Val); 542} 543 544void 545AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) { 546 llvm::Value *Val = DestPtr; 547 548 if (!Val) // Create a temporary variable. 549 Val = CGF.CreateMemTemp(E->getType(), "tmp"); 550 551 if (E->requiresZeroInitialization()) 552 EmitNullInitializationToLValue(LValue::MakeAddr(Val, 553 // FIXME: Qualifiers()? 554 E->getType().getQualifiers()), 555 E->getType()); 556 557 CGF.EmitCXXConstructExpr(Val, E); 558} 559 560void AggExprEmitter::VisitCXXExprWithTemporaries(CXXExprWithTemporaries *E) { 561 llvm::Value *Val = DestPtr; 562 563 CGF.EmitCXXExprWithTemporaries(E, Val, VolatileDest, IsInitializer); 564} 565 566void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) { 567 llvm::Value *Val = DestPtr; 568 569 if (!Val) { 570 // Create a temporary variable. 571 Val = CGF.CreateMemTemp(E->getType(), "tmp"); 572 } 573 LValue LV = LValue::MakeAddr(Val, Qualifiers()); 574 EmitNullInitializationToLValue(LV, E->getType()); 575} 576 577void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) { 578 llvm::Value *Val = DestPtr; 579 580 if (!Val) { 581 // Create a temporary variable. 582 Val = CGF.CreateMemTemp(E->getType(), "tmp"); 583 } 584 LValue LV = LValue::MakeAddr(Val, Qualifiers()); 585 EmitNullInitializationToLValue(LV, E->getType()); 586} 587 588void 589AggExprEmitter::EmitInitializationToLValue(Expr* E, LValue LV, QualType T) { 590 // FIXME: Ignore result? 591 // FIXME: Are initializers affected by volatile? 592 if (isa<ImplicitValueInitExpr>(E)) { 593 EmitNullInitializationToLValue(LV, T); 594 } else if (T->isReferenceType()) { 595 RValue RV = CGF.EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0); 596 CGF.EmitStoreThroughLValue(RV, LV, T); 597 } else if (T->isAnyComplexType()) { 598 CGF.EmitComplexExprIntoAddr(E, LV.getAddress(), false); 599 } else if (CGF.hasAggregateLLVMType(T)) { 600 CGF.EmitAnyExpr(E, LV.getAddress(), false); 601 } else { 602 CGF.EmitStoreThroughLValue(CGF.EmitAnyExpr(E), LV, T); 603 } 604} 605 606void AggExprEmitter::EmitNullInitializationToLValue(LValue LV, QualType T) { 607 if (!CGF.hasAggregateLLVMType(T)) { 608 // For non-aggregates, we can store zero 609 llvm::Value *Null = llvm::Constant::getNullValue(CGF.ConvertType(T)); 610 CGF.EmitStoreThroughLValue(RValue::get(Null), LV, T); 611 } else { 612 // There's a potential optimization opportunity in combining 613 // memsets; that would be easy for arrays, but relatively 614 // difficult for structures with the current code. 615 CGF.EmitNullInitialization(LV.getAddress(), T); 616 } 617} 618 619void AggExprEmitter::VisitInitListExpr(InitListExpr *E) { 620#if 0 621 // FIXME: Assess perf here? Figure out what cases are worth optimizing here 622 // (Length of globals? Chunks of zeroed-out space?). 623 // 624 // If we can, prefer a copy from a global; this is a lot less code for long 625 // globals, and it's easier for the current optimizers to analyze. 626 if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) { 627 llvm::GlobalVariable* GV = 628 new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true, 629 llvm::GlobalValue::InternalLinkage, C, ""); 630 EmitFinalDestCopy(E, LValue::MakeAddr(GV, Qualifiers())); 631 return; 632 } 633#endif 634 if (E->hadArrayRangeDesignator()) { 635 CGF.ErrorUnsupported(E, "GNU array range designator extension"); 636 } 637 638 // Handle initialization of an array. 639 if (E->getType()->isArrayType()) { 640 const llvm::PointerType *APType = 641 cast<llvm::PointerType>(DestPtr->getType()); 642 const llvm::ArrayType *AType = 643 cast<llvm::ArrayType>(APType->getElementType()); 644 645 uint64_t NumInitElements = E->getNumInits(); 646 647 if (E->getNumInits() > 0) { 648 QualType T1 = E->getType(); 649 QualType T2 = E->getInit(0)->getType(); 650 if (CGF.getContext().hasSameUnqualifiedType(T1, T2)) { 651 EmitAggLoadOfLValue(E->getInit(0)); 652 return; 653 } 654 } 655 656 uint64_t NumArrayElements = AType->getNumElements(); 657 QualType ElementType = CGF.getContext().getCanonicalType(E->getType()); 658 ElementType = CGF.getContext().getAsArrayType(ElementType)->getElementType(); 659 660 // FIXME: were we intentionally ignoring address spaces and GC attributes? 661 Qualifiers Quals = CGF.MakeQualifiers(ElementType); 662 663 for (uint64_t i = 0; i != NumArrayElements; ++i) { 664 llvm::Value *NextVal = Builder.CreateStructGEP(DestPtr, i, ".array"); 665 if (i < NumInitElements) 666 EmitInitializationToLValue(E->getInit(i), 667 LValue::MakeAddr(NextVal, Quals), 668 ElementType); 669 else 670 EmitNullInitializationToLValue(LValue::MakeAddr(NextVal, Quals), 671 ElementType); 672 } 673 return; 674 } 675 676 assert(E->getType()->isRecordType() && "Only support structs/unions here!"); 677 678 // Do struct initialization; this code just sets each individual member 679 // to the approprate value. This makes bitfield support automatic; 680 // the disadvantage is that the generated code is more difficult for 681 // the optimizer, especially with bitfields. 682 unsigned NumInitElements = E->getNumInits(); 683 RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl(); 684 unsigned CurInitVal = 0; 685 686 if (E->getType()->isUnionType()) { 687 // Only initialize one field of a union. The field itself is 688 // specified by the initializer list. 689 if (!E->getInitializedFieldInUnion()) { 690 // Empty union; we have nothing to do. 691 692#ifndef NDEBUG 693 // Make sure that it's really an empty and not a failure of 694 // semantic analysis. 695 for (RecordDecl::field_iterator Field = SD->field_begin(), 696 FieldEnd = SD->field_end(); 697 Field != FieldEnd; ++Field) 698 assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed"); 699#endif 700 return; 701 } 702 703 // FIXME: volatility 704 FieldDecl *Field = E->getInitializedFieldInUnion(); 705 LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestPtr, Field, 0); 706 707 if (NumInitElements) { 708 // Store the initializer into the field 709 EmitInitializationToLValue(E->getInit(0), FieldLoc, Field->getType()); 710 } else { 711 // Default-initialize to null 712 EmitNullInitializationToLValue(FieldLoc, Field->getType()); 713 } 714 715 return; 716 } 717 718 // If we're initializing the whole aggregate, just do it in place. 719 // FIXME: This is a hack around an AST bug (PR6537). 720 if (NumInitElements == 1 && E->getType() == E->getInit(0)->getType()) { 721 EmitInitializationToLValue(E->getInit(0), 722 LValue::MakeAddr(DestPtr, Qualifiers()), 723 E->getType()); 724 return; 725 } 726 727 728 // Here we iterate over the fields; this makes it simpler to both 729 // default-initialize fields and skip over unnamed fields. 730 for (RecordDecl::field_iterator Field = SD->field_begin(), 731 FieldEnd = SD->field_end(); 732 Field != FieldEnd; ++Field) { 733 // We're done once we hit the flexible array member 734 if (Field->getType()->isIncompleteArrayType()) 735 break; 736 737 if (Field->isUnnamedBitfield()) 738 continue; 739 740 // FIXME: volatility 741 LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestPtr, *Field, 0); 742 // We never generate write-barries for initialized fields. 743 LValue::SetObjCNonGC(FieldLoc, true); 744 if (CurInitVal < NumInitElements) { 745 // Store the initializer into the field. 746 EmitInitializationToLValue(E->getInit(CurInitVal++), FieldLoc, 747 Field->getType()); 748 } else { 749 // We're out of initalizers; default-initialize to null 750 EmitNullInitializationToLValue(FieldLoc, Field->getType()); 751 } 752 } 753} 754 755//===----------------------------------------------------------------------===// 756// Entry Points into this File 757//===----------------------------------------------------------------------===// 758 759/// EmitAggExpr - Emit the computation of the specified expression of aggregate 760/// type. The result is computed into DestPtr. Note that if DestPtr is null, 761/// the value of the aggregate expression is not needed. If VolatileDest is 762/// true, DestPtr cannot be 0. 763// 764// FIXME: Take Qualifiers object. 765void CodeGenFunction::EmitAggExpr(const Expr *E, llvm::Value *DestPtr, 766 bool VolatileDest, bool IgnoreResult, 767 bool IsInitializer, 768 bool RequiresGCollection) { 769 assert(E && hasAggregateLLVMType(E->getType()) && 770 "Invalid aggregate expression to emit"); 771 assert ((DestPtr != 0 || VolatileDest == false) 772 && "volatile aggregate can't be 0"); 773 774 AggExprEmitter(*this, DestPtr, VolatileDest, IgnoreResult, IsInitializer, 775 RequiresGCollection) 776 .Visit(const_cast<Expr*>(E)); 777} 778 779LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) { 780 assert(hasAggregateLLVMType(E->getType()) && "Invalid argument!"); 781 Qualifiers Q = MakeQualifiers(E->getType()); 782 llvm::Value *Temp = CreateMemTemp(E->getType()); 783 EmitAggExpr(E, Temp, Q.hasVolatile()); 784 return LValue::MakeAddr(Temp, Q); 785} 786 787void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr, 788 llvm::Value *SrcPtr, QualType Ty, 789 bool isVolatile) { 790 assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex"); 791 792 if (getContext().getLangOptions().CPlusPlus) { 793 if (const RecordType *RT = Ty->getAs<RecordType>()) { 794 CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl()); 795 assert((Record->hasTrivialCopyConstructor() || 796 Record->hasTrivialCopyAssignment()) && 797 "Trying to aggregate-copy a type without a trivial copy " 798 "constructor or assignment operator"); 799 // Ignore empty classes in C++. 800 if (Record->isEmpty()) 801 return; 802 } 803 } 804 805 // Aggregate assignment turns into llvm.memcpy. This is almost valid per 806 // C99 6.5.16.1p3, which states "If the value being stored in an object is 807 // read from another object that overlaps in anyway the storage of the first 808 // object, then the overlap shall be exact and the two objects shall have 809 // qualified or unqualified versions of a compatible type." 810 // 811 // memcpy is not defined if the source and destination pointers are exactly 812 // equal, but other compilers do this optimization, and almost every memcpy 813 // implementation handles this case safely. If there is a libc that does not 814 // safely handle this, we can add a target hook. 815 816 // Get size and alignment info for this aggregate. 817 std::pair<uint64_t, unsigned> TypeInfo = getContext().getTypeInfo(Ty); 818 819 // FIXME: Handle variable sized types. 820 821 // FIXME: If we have a volatile struct, the optimizer can remove what might 822 // appear to be `extra' memory ops: 823 // 824 // volatile struct { int i; } a, b; 825 // 826 // int main() { 827 // a = b; 828 // a = b; 829 // } 830 // 831 // we need to use a different call here. We use isVolatile to indicate when 832 // either the source or the destination is volatile. 833 834 const llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType()); 835 const llvm::Type *DBP = 836 llvm::Type::getInt8PtrTy(VMContext, DPT->getAddressSpace()); 837 DestPtr = Builder.CreateBitCast(DestPtr, DBP, "tmp"); 838 839 const llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType()); 840 const llvm::Type *SBP = 841 llvm::Type::getInt8PtrTy(VMContext, SPT->getAddressSpace()); 842 SrcPtr = Builder.CreateBitCast(SrcPtr, SBP, "tmp"); 843 844 if (const RecordType *RecordTy = Ty->getAs<RecordType>()) { 845 RecordDecl *Record = RecordTy->getDecl(); 846 if (Record->hasObjectMember()) { 847 unsigned long size = TypeInfo.first/8; 848 const llvm::Type *SizeTy = ConvertType(getContext().getSizeType()); 849 llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size); 850 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr, 851 SizeVal); 852 return; 853 } 854 } else if (getContext().getAsArrayType(Ty)) { 855 QualType BaseType = getContext().getBaseElementType(Ty); 856 if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) { 857 if (RecordTy->getDecl()->hasObjectMember()) { 858 unsigned long size = TypeInfo.first/8; 859 const llvm::Type *SizeTy = ConvertType(getContext().getSizeType()); 860 llvm::Value *SizeVal = llvm::ConstantInt::get(SizeTy, size); 861 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr, 862 SizeVal); 863 return; 864 } 865 } 866 } 867 868 Builder.CreateCall5(CGM.getMemCpyFn(DestPtr->getType(), SrcPtr->getType(), 869 IntPtrTy), 870 DestPtr, SrcPtr, 871 // TypeInfo.first describes size in bits. 872 llvm::ConstantInt::get(IntPtrTy, TypeInfo.first/8), 873 Builder.getInt32(TypeInfo.second/8), 874 Builder.getInt1(isVolatile)); 875} 876